package com.springtemplate.security.Util;

import org.springframework.util.DigestUtils;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.spec.IvParameterSpec;

/**
 * @author Qiu Ping
 * @description 加密工具类
 * @date 2019/8/14
 */
public class EncryptUtils {

	private static String strKey = "Passw0rd", strParam = "Passw0rd";

	/**
	 * 对称加密
	 * @param source
	 * @return
	 * @throws Exception
	 */
	public static String desEncrypt(String source) throws Exception {
		if (source == null || source.length() == 0){
			return null;
		}
		Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
		DESKeySpec desKeySpec = new DESKeySpec(strKey.getBytes("UTF-8"));
		SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
		SecretKey secretKey = keyFactory.generateSecret(desKeySpec);
		IvParameterSpec iv = new IvParameterSpec(strParam.getBytes("UTF-8"));
		cipher.init(Cipher.ENCRYPT_MODE, secretKey, iv);
		return byte2hex(
				cipher.doFinal(source.getBytes("UTF-8"))).toUpperCase();
	}

	public static String byte2hex(byte[] inStr) {
		String stmp;
		StringBuffer out = new StringBuffer(inStr.length * 2);
		for (int n = 0; n < inStr.length; n++) {
			stmp = Integer.toHexString(inStr[n] & 0xFF);
			if (stmp.length() == 1) {
				// 如果是0至F的单位字符串，则添加0
				out.append("0" + stmp);
			} else {
				out.append(stmp);
			}
		}
		return out.toString();
	}


	public static byte[] hex2byte(byte[] b) {
		if ((b.length % 2) != 0){
			throw new IllegalArgumentException("长度不是偶数");
		}
		byte[] b2 = new byte[b.length / 2];
		for (int n = 0; n < b.length; n += 2) {
			String item = new String(b, n, 2);
			b2[n / 2] = (byte) Integer.parseInt(item, 16);
		}
		return b2;
	}

	/**
	 * 对称解密
	 * @param source
	 * @return
	 * @throws Exception
	 */
	public static String desDecrypt(String source) throws Exception {
		if (source == null || source.length() == 0){
			return null;
		}
		byte[] src = hex2byte(source.getBytes());
		Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
		DESKeySpec desKeySpec = new DESKeySpec(strKey.getBytes("UTF-8"));
		SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
		SecretKey secretKey = keyFactory.generateSecret(desKeySpec);
		IvParameterSpec iv = new IvParameterSpec(strParam.getBytes("UTF-8"));
		cipher.init(Cipher.DECRYPT_MODE, secretKey, iv);
		byte[] retByte = cipher.doFinal(src);
		return new String(retByte);
	}

	/**
	 * 密码加密
	 * @param password
	 * @return
	 */
	public static String encryptPassword(String password){
		return  DigestUtils.md5DigestAsHex(password.getBytes());
	}
}